This invention relates to composite sheet material and more particularly to a composite sheet material comprising rows of stitches formed in a base sheet.
The present Applicants previously developed a composite sheet material which is a stitched crepe paper and the manufacture of which is described and claimed in U.K. Pat. No. 1,422,940. This stitched crepe paper product has properties which make it particularly suitable as a backing for a carpet underlay, the product having dimensional stability and being capable of adhesion to a sheet of foamed or sponge rubber.
The present Applicants have now developed an improved method of making a composite sheet material having longitudinal rows of stitches to provide dimensional stability, but the method of the present invention enables the product to be stronger and thicker than the product of U.K. Pat. No. 1,422,940, and to have greater depth in the gaps between the stitches thus making the product more suitable for adhering to materials other than rubber materials, for example synthetic resin materials in any suitable form.